Mesozoic Era fossil dinosaur bones and eggs located in Patagonia

A 70-million-year-old find of fossilized bones and unique eggs by an Argentina-Swedish research team has been located in Patagonia. The mysterious creature belongs to the birdlike Alvarezsauridae dinosaur family.

The Alvarezsauridea dinosaur represents the latest survivor of its kind---found in Gondwana on December 2010, the southern landmass in the Mesozoic Era. Referred to as the Age of Reptiles, this was an interval of geological time from 250 million years ago to 65 million years ago.

Science Daily reports, "The bird skeleton was first discovered by Dr. Powell, but has now been described and named Bonapartenykus ultimus in honor of Dr. José Bonaparte who in 1991 discovered the first Alvarezsaurid in Patagonia."

They had a bird-like skull, tiny teeth-carrying jaws, typical robust but considerably abbreviated forearms, and one of their manual digits that developed massive phalanges including enormous claw.

Two of the dinosaur's eggs were lying near the bones of its hind limb, the first time any eggs of the Alvarezsaurid dinosaurs were found this close to the skeletal remains, reported Dr. Martin Kundrát, dinosaur expert from the group of Professor Per Erik Ahlberg at Uppsala University. "This shows that basal alvarezsaurids persisted in South America until Latest Cretaceous times."

It is thought that the two eggs near the Alvarezsaurids had been located inside the female when she died. Some of the eggs had been incubated, containing embryos at advanced stages of their development.Martin Kundrát analyzed the eggshells, finding that it did not belong to any known category of the eggshell microstructure-based taxonomy.